To follow on from our holiday we went glamping at a place called Jollydays (http://www.jollydaysluxurycamping.co.uk/). The campsite was huge in a woodland with safari like tents. We hired a luxury tent with proper beds, a 2 ring gas stove and a shower and toilet. The tent was huge, but dark even in the daytime. The beds were super comfortable. The kids had a great time playing in the woods with other children. WE went off at 8 and came back to eat and we rounded them up when it was dark. They loved the wooden rope swings, toasting marshmallows on the central camp fire (I was so impressed as they shared their marshmallows with all their new friends without being asked) and just the freedom camping offers. The only downsides was the cost compared to normal camping and they said they sold cake and marshmallows in the tea tent which I never saw any marshmallows and the cakes seemed to be the same all the time we were there. BUT it was a fab holiday and the kids are keen to go back.
Whilst we were in York we visited the Jorkvik centre which was all about York's viking history and the minister.